1. Field of the Invention
The present invention relates to high-intensity staged-air vortex burners. More particularly, the present invention relates to a novel and improved staged-air vortex burner which is suitable for utilizing low heating value fuel under forced-draft service.
2. Description of the Prior Art
In U.S. Pat. No. 3,476,494, there is disclosed a vortex burner which includes a cylindrical combustion chamber and a constant diameter air swirl chamber, the functions of which are to contain and confine the burning process and to achieve a high degree of mixing to ensure completeness of combustion.
In U.S. Pat. No. 3,671,173 there is disclosed an improved high-intensity burner, which eliminates the necessity for a combustion chamber but which nonetheless achieves a high temperature in a relatively small but structurally unconfined volume. The device disclosed in that patent relies upon the principal of vortex air flow to achieve the high temperature in the structurally unconfined volume.
In U.S. Pat. No. 3,746,499, there is disclosed a chamberless vortex burner which employs a swirling auxiliary air flow to achieve a high concentrated degree of fuel-air mixing and high temperature in a relatively small but structurally unconfined volume.
In U.S. Pat. No. 4,175,920, there is disclosed a staged-air vortex chamberless burner which is provided with at least two fuel supply means, making it possible to fire fuel simultaneously at least at two different flow paths.
Each of the foregoing burners, and particularly the last three, have been proven to be entirely satisfactory for their intended purposes. They are not satisfactory, however, for combusting low heating value, i.e., low Btu, gas fuels under forced-draft service.